Android Question Canvas Drawtext parameters

[ducphu]

Hi all,

Can some one explain to me in details the parameters for Canvas.Drawtext command. I read through the document but not well understanded. Especially the x,y origin points. Thank you.

 

[derez]

The parameters are like those of a label's text. The x is like the label's top and the y is like the label's bottom (so if you draw text on the top of a panel - it will not show).

 

[klaus]

Look at page 302 in the User's Guide.
EDIT:
It's in the Beginner's Guide not in the User's Guide.

 

[ducphu]

Let say I have a bitmap of 100x20(WxH) and I want to draw a text like "Welcome", what does x and y mean? Is (x,y) point the point where it starts to draw, i.e "W" character? How does the alignment(left,center,right) actually effect?

 

[DonManfred]

Look at page 302 in the User's Guide.

Page 302 of 182? Did you mean the BeginnersGuide?

Edit: Yes... It´s in the BeginnersGuide

 

[ducphu]

Thanks Don, very nice explaination. Can I ask to which the x and y value refer to, the activity size or the bitmap? I'm working with a widget which an imageview (146x26) I create a bitmap wiith the same size 146x26. According to your post, if I draw a text at 73x26 with center alignment, the text should be draw at the center and bottom of the bitmap/imageview. But when I test it on my phone, it doesn't.

 

[klaus]

How do you define the Canvas ?

 

[DonManfred]

Thanks Don, very nice explaination.

I just make a Screenshot from @klaus Beginners Guide page 302.

I believe it is in the Canvas-dimensions (Width and Height)

 

[ducphu]

Dim Font As Typeface
        Dim Canvas As Canvas
        Dim imgCC As Bitmap
        Font = Typeface.LoadFromAssets("CORSIVA.ttf")
        imgCC.InitializeMutable(146dip,26dip)
        Canvas.Initialize2(imgCC)
        Canvas.DrawText("A", 0, 26, Font, 18, Colors.White, "LEFT")
        Canvas.DrawText("B", 73, 26, Font, 18, Colors.White, "LEFT")
        Canvas.DrawText("C", 146, 26, Font, 18, Colors.White, "LEFT")
        Canvas.DrawText("A", 0, 26, Font, 18, Colors.Blue, "CENTER")
        Canvas.DrawText("B", 73, 26, Font, 18, Colors.Blue, "CENTER")
        Canvas.DrawText("C", 146, 26, Font, 18, Colors.Blue, "CENTER")
    End If

Then I draw on a imageviewer 146x26. Attached the screenshoot. The grey line is draw across the widget from 1 end to the other end, and is at the bottom of the imageview.

 

[DonManfred]

shouldn´t it be

Canvas.DrawText("A", 0dip, 26dip, Font, 18, Colors.White, "LEFT")

instead of

Canvas.DrawText("A", 0, 26, Font, 18, Colors.White, "LEFT")

? The same for all others too...

 

[ducphu]

shouldn´t it be

Canvas.DrawText("A", 0dip, 26dip, Font, 18, Colors.White, "LEFT")

instead of

Canvas.DrawText("A", 0, 26, Font, 18, Colors.White, "LEFT")

? The same for all others too...

Yeah yeah Don, you are right. My stupid mistake.

 

[DonManfred]

If you find my answer useful please click on like on that post.

 

[iamfanghan]

Hi there, is there coding to erase the graph so that it wont overlap with the new graph in the same panel?

 

[DonManfred]

clear the canvas and draw all again

 

[iamfanghan]

clear the canvas and draw all again

How do i do that sir? Would glad if you will guide me the code needed